Shimano Ice Tech Rotors - worth it?

Following a post earlier I'm looking at getting a set of Shimano SLX Disc brakes as an Xmas pressie to me from my family and I wondered if the Ice Tech Rotors are worth the extra over a standard rotor. I understand the premise but would I really be missing much that much or are they worth the extra?

Also should I go 203mm front and rear or 203mm front, 180mm rear.

Oh decisions, decisions. As an idea of intended use they'd be going on a Mondraker Foxy, I'd class myself as Clydesdale build and I ride in North Scotland - Laggan, Learnie and Monster Trails mostly as well as a bit of back yard woodsy stuff.

Not usually this indecisive but I've assured the other half that these are to completely complete the bike so I want to get it right.

Bob - IMHO, the SLX versions don't make much difference. , over non IT versions. The XTs yep, on a long descent you do feel some improvements.

I've had a few sets of the SLX Brakes with different rotor types/sizes.

Current bike has XT brakes. Came with SLX IT rotors, 180/180 on a Cube Stereo 29. I'm 120kg and weight/wheel combo left me feeling underwhelmed with stopping power. Changed to XT rotors 203/180 and saw a huge improvement.

The original pads in my experience don't last long, so I swapped out for Uberbike RaceTech., again big improvement. Great stopping in all conditions, without being grabby.

No it didn't. It's the aluminium sandwich construction for better heat dissipation which makes a rotor "Ice-tech", and that only comes on XT, XTR and Saint level rotors.

SLX rotors are RT-67 for centrelock, and RT76 for 6-bolt, and are solid steel. XT rotors are RT81 for centrelock and RT86 for 6-bolt and are Ice-tech.

Similarly, its the finned pads which make a brake "Ice-tech", there's nothing different about the calliper.

Thankfully, the rotors and finned pads are interchangeable across all of Shimano's latest lineup of brakes, so you can mix and match to your hearts content.

Personally, I started with non-icetech rotors & pads, thinking it was all just a marketing gimmick by Shimano. But my brakes were overheating at the end of long descents, so I switched both bikes (one SLX, one XT) to all Ice-tech and haven't had a problem since.

To answer the OP's question - would Ice-tech rotors make a difference? Probably not in 'normal' riding, but given the small difference in cost it's good insurance for that one time your brakes overheat on a long downhill!

As for sizes, I'm no lightweight and run 180 front and 160 rear on both bikes. The current Shimano brakes have stupidly strong stopping power, and I couldn't see myself wanting more, unless I was heading off to the Alps - and then it'd be for heat dissipation again not stopping power.

You do need to be careful with icetech rotors when transporting bikes-they are definitely easier to bend accidentally with rough handling than 'solid' stainless. Not really an issue as long as you remember.......

There are some reports online (including German magazine reviews) of them delaminating on long descents too...

How often do you over heat 203mm rotors? That would be some serious brake dragging. At the larger rotor end of the spectrum you might as well get a lighter rotor like Hope or similar. The Shimano would most likely work equally well but I can't see you gaining anything.

Champion thanks for the views and info folks. Gone with the CRC XT versions. Bit cheeky used the £10 discount posted on the other thread, twice, by setting up a second account. 203 front and 180 rear. Just used to the big rotors as my older set have them so ample power available.

Re the Merlin cycles thread - just had a quick butchers at why the internet thinks Merlin have gone down the drain. Would appear that they most likely have not, and the poster in question was "jumpin the gun" somewhat. Didn't read all 100+ posts though, but pretty sure that Shimano are at fault instead with a gazillion different disc options - who wouldn't be confused.